1. Field of the Invention
The present invention relates to a Coupling Device for metal pipes with innovative packing structure.
2. Discussion of the Conventional Art in the Similar Field
Drawings (4) and (5) are enclosed hereby for explaining the conventional coupling device with conventional packing structure.
A conventional coupling device (FIG. 4) for metal pipes comprises a Cup-joint(A), a Packing Bushing(B), a Padding Bushing(C) and a Bridging Connector(D). The Cup-joint(A) featuring a Side-ring(A1) at one end yields a Holding Hole(A11) and a Confining Face(A12) on the inner face inside the Cup-joint itself, wherein the Packing Bushing(B) and the Padding Bushing(C) are held and confined. The Packing Bushing(B) featuring a ring of Packing Fortifiers(B1) on one inner edge is coupled and confined in the Confining Face(A12) of the Cup-joint(A) and in turn the Padding Bushing(C) featuring a Converging Ending(C1) is coupled and confined inside the Packing Bushing(B), such that the Fortifier Ring(B1) is coupled to the Side-ring(A1) of the Cup-joint and the Converging Ending(C1) is coupled to the Guiding Face(D1) of the Bridging Connector(D). When (A), (B), (C) and (D) four parts are fixed together, the conventional Coupling Device is completed to yield a Holding Hole(A11) for holding two ends of two separate metal pipes together.
The feature of the conventional Coupling Device is that, when the Cup-joint(A) is screwed to the Bridging Connector(D), the Converging Ending(C1) will get into the Guiding Face(D1) and thus seals up the gap in between the connector(D) and the Metal Pipe(E). On the other hand, the whole Padding Bushing(C) is pushed by the Guiding Face (D1) against the Fortifiers(B1) of the Packing Bushing. As a result, the indentation structure of the Fortifier Ring are forced by the Padding Bushing(C) to change form and clasp the metal pipe tightly. The sealing effect of the Padding Bushing and the clasping force of the Fortifiers will increase as the force to screw the Cup-joint to the Bridging Connector increases. In practice, since the screwing force is only conducted by the Confining Face(A12) of the Cup-joint(A), it requires a great force to push the Converging Ending in and change the shape of the Fortifier-indentation. The conventional coupling device is obvious in a crude and unrefined stage. It requires innovation.